Molecular drug targets for scabies: a medicinal chemistry perspective

The current available diagnostic tools and treatments of scabies and scabies variants: An updated narrative review

Scabies is a neglected tropical disease that continues to have global impacts and long-term health consequences. It is caused by the mite Sarcoptes scabei var. hominis, which is an obligate ectoparasite that lives in the epidermis of the human skin. Scabies is common in poor communities due to overcrowding in places like old age homes, prisons, and homeless and displaced children. However, developed countries are also susceptible to scabies infestations, such as in institutional outbreaks or small epidemics under war conditions or during natural disasters. The diagnosis of scabies may be assisted by invasive and noninvasive tools; However, the history and examination findings are usually adequate to confirm the clinical suspicion. Here, we present an updated review of scabies by focusing on the diagnostic approaches, treatment, and prevention of scabies.

Biophysical description of Bromosulfophthalein interaction with the 28-kDa glutathione transferase from Schistosoma japonicum

Glutathione transferases (GSTs) are major detoxification enzymes vital for the survival and reproduction of schistosomes during infection in humans. Schistosoma encode two GST isoenzymes, the 26- and 28-kDa isoforms, that show different substrate specificities and cellular localisations. Bromosulfophthalein (BSP) has been identified and characterised as a potent 26-kDa Schistosoma japonicum GST (Sj26GST) inhibitor with an anthelmintic potential. This study describes the structure, function, and ligandin properties of the 28-kDa Schistosoma japonicum GST (Sj28GST) towards BSP. Enzyme kinetics show that BSP is a potent enzyme inhibitor, with a specific activity decreases from 60.4 µmol/min/mg to 0.0742 µmol/min/mg and an IC₅₀ in the micromolar range of 0.74 µM. Far-UV circular dichroism confirmed that purified Sj28GST follows a typical GST fold, which is predominantly alpha-helical. Fluorescence spectroscopy suggests that BSP binding occurs at a site distinct from the glutathione-binding site (G-site); however, the binding does not alter the local G-site environment. Isothermal titration calorimetry studies show that the binding of BSP to Sj28GST is exergonic (∆G°= -33 kJ/mol) and enthalpically-driven, with a stoichiometry of one BSP per dimer. The stability of Sj28GST (∆G_(H2O) = 4.7 kcal/mol) is notably lower than Sj26GST, owing to differences in the enzyme's dimeric interfaces. We conclude that Sj28GST shares similar biophysical characteristics with Sj26GST based on its kinetic properties and susceptibility to low concentrations of BSP. The study supports the potential benefits of re-purposing BSP as a potential drug or prodrug to mitigate the scourge of schistosomiasis.